Control mechanism for variable-speed transmissions



w y w M. MALLORY 2,499,071

CONTROL MECHANISM FOR VARIABLE SPEED TRANSMISSIONS Feb. 28, 1950 FiledMarch 29, 1945 INVENTOR. Mano/7 Mafia/"y Patented Feb. 28, 1950 UNITEDOFFICE :CONTROL MECHANISM FOR VARIABL SPEED TRANSMISSIONS 1' MarlonMallory, Detroit, Mich. I

Application March29, 1945, Serial No. 585,548

. 1 This invention relates to a. control mechanism for a variable speedtransmission for an internal combustion engine. 'It is the object ofthis invention to produce a control mechanism for a variable Speed transmission for an internal combustion engine which will automatically varythe driving ratio of the transmission in accordance with the load on Ithe engine.

My invention also contemplates a change speed control mechanism for aninternal combustion engine which is of simple structure, reliable andefiicient in operation, and economical to produce. In the operation ofan internal combustion engine the vacuum in the intake manifoldincreases as the load on the engine decreases and the vacuum in theintake manifold decreases as the load on the engine is increased.Therefore, the engine should have a greater leverage or a lower drivingratio or speed over the unit it is driving when more load is placed onthe unit and the engine should have less leverage or a higher drivingratio or speed over the unit it is driving when the load placed on theunit is decreased. My change speed control mecha nism accomplishes thisresult. 1 The drawing illustrates my change speed driving mechanism foran internal combustion engine. The elements illustrated in the drawingsare referenced as follows: internal combustion engine I, reciprocatingpiston 2, connecting rod 3, engine driving shaft 4, engine intakepassageway 5, throttle valve 6, stub shaft 1 splined in driving shaft 4as at 8, driving pulley 9, driven wheel l fixed on driven shaft H,servo-motor l2 comprising ilexible diaphragm l3, compression spring l4,suction chamber l5; conduit I 6' connecting suction chamber IS withintake passageway 5, lever ll, pivot l8 for lever IT on the-fixedsupport l9, collar 20 fixed on shaft 1, yoke 2! on the free end of leverI l interengaging collar 20, connecting rod 22 pivoted on shaft I1 andfixed to diaphragm l3, air bleed conduit 23 connected into conduit l6and communicating with passageway 24 in shaft 25, air bleed orifice 26in valve housing 21 fixed on shaft 25, valve 28 on piston 29,by-passageway 30 in piston 29, tension spring 3| tending to holdcentrifugally unbalanced valve 28 open, drive shafts 32 and 33 andbeveled gear sets 34, 35 and 36 for driving shaft 25 ofl of the enginecrankshaft 4.

The operation of my device is as follows: Assume that driven wheel l0and driven shaft 7 4 Claims. (01. 74-3565) H are driving anything, such,for example, as 5 the wheels of an automotive vehicle, a saw-mill, or acorn grinder. While engine I runs, pulley 9, which is of frictionmaterial, drives wheel ID. The engine, as shown, is operating under fullload or wide open throttle. At lower engine speeds itis desirable tooperate the transmission in low gear, that is, at a lower driving ratiobetween driving pulley 9 and driven wheel I!) to avoid roughness.Therefore, at lower engine speeds, I arrange centrifugal valve 28 sothat it will be open and air bleed the servo-motor 12. Sincecentrifugally balanced valve 28 is open, air bleeds into suction chamberl5 through orifice 26, passageways 30, 24 and conduits 23, 16. v Sincethe pressure in chamber [5 is substantially atmospheric, spring l4,acting through lever ll, has shifted stub shaft 1 and pulley 9 to theleft thereby effecting a low driving ratio between pulley 9- and drivenshaft ll. As the engine picks up speed, valve 28 will close and thevacuum in the intake passageway will build up a vacuum in chamber I 5thereby causing flexible diaphragm l3 to move toward the left againstcompression spring l4 and swing lever l1 counterclockwise, which movespulley 9 to the right thereby increasing the driving ratio betweendriving shaft! and driven shaft II, that is, as pulley 9 moves towardshaft l l the leverage of the engine over driven shaft ll is decreasedand it will take fewer revolutions of pulley 9 to effect each revolutionof wheel Ill.

In the event throttle 6 is moved toward an open position, the vacuumwill decrease in chamber I 5 causing lever I! to move to the right.which moves pulley 9 outwardly on the wheel [0 and changes the gearratio so that the engine has greater leverage over the unit it isdriving when the vacuum is decreased in the intake manifold.

In the event the load of the engine is decreased by moving throttle 6toward a closed position, the vacuum will increase, causing lever I! tomove to the left and pulley 9 to move to the right on wheel Hi. Thischanges the gear ratio between the engine and the unit it is driving sothe engine has less leverage over the driven unit, and of course theengine makes less revolutions per revolution of wheel Ill when thevacuum is high in the manifold or the engine is operating under lightload than it does when the vacuum is low in the manifold and the engineis operating under heavier load.

It is, of course, understood that pulleys and wheel ID are shown merelyfor illustrative purposes and not by way of limitation. Obviously,

any of the well known change speed transmissions can be substituted forthe change speed transmission exemplified by pulley 9 and wheel I0.

I claim:

1. A transmission control for an internal combustion engine having anintake passageway, comprising a driving shaft, a driven shaft, variableratio transmission mechanism between said driving and driven shafts, aservo-motor connected to said variable ratio drive transmissionmechanism, a passageway connecting said servomotor with said intakepassageway whereby said servo-motor responds to changes in intakepassageway pressure to actuate said variable ratio transmissionmechanism and vary the driving ratio between the driving and drivenshafts, a centrifugally controlled air bleed valve mechanism actuated inaccordance with the speed of the engine and arranged to bleed air intothe servo-motor when the engine is operating below a predetermined speedwhereby the servo-motor maintains a low driving ratio between the drivenand driving shafts.

2. A change speed transmission control for an internal'combustion enginehaving an'intake passageway and a throttle valve for controlling theflow of motive fluid through said passageway, comprising a drivingshaft, a driven shaft, a change speed transmission between said drivingand driven shafts, pressure actuated means having an operativeconnection with said change speed transmission, a conduit connectingsaid pressure actuated means with the intake passageway on the engineside of said throttle valve whereb as the vacuum rises in the intakepassageway. such as occurs when the speed of the engine increases or thethrottle valve is moved toward closed position and said below mentionedfluid bleed is closed, the pressure actuated means responds to saidincrease in vacuum to change the speed of the transmission to a higherdriving speed and thereby decrease the leverage of the driving shaftover the driven shaft, a fluid bleed for said pressure actuated means,means actuated in accordance with the speed of the engine forcontrolling said fiuid bleed, said last mentioned means being arrangedto open said fluid bleed below a predetermined engine speed to therebybleed down the vacuum in said pressure actuated means whereby thepressure actuated servo-motor responds to changes in intake passagewaypressure to actuate said variable ratio transmission mechanism and varythe driving ratio between the driving and driven shafts, an airbleedorific'e for bleeding air into said servomotor, and a centrifugalvalve actuated in accordance with the speed of the engine forcontrolling said air bleedorifice, said centrifugal valve closing saidair bleed orifice when the engine is operating above a predeterminedspeed whereby the servo-motor maintains a high driving ratio between thedriven and driving shafts, said centrifugal valve opening said air bleedorifice when the engine is operating below said predetermined speedwhereby the servo-motor responds to lower the driving ratio between thedriven and driving shafts.

4. The combination as set forth in claim 2 wherein the fluid bleed forsaid pressure actuated means bleeds to atmosphere and wherein the meansfor controlling said fluid bleed comprises a centrifugally unbalancedvalve rotated in accordance with the speed of the engine and arranged toclose said air bleed when the engine is operating above a predeterminedspeed.

MARION MALLORY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,783,931 Tenney et al Dec. 2,1930 1,993,544 Fleischel Mar. 5, 1935 2,094,418 Swanson Sept. 28, 19372,362,655 Mallory Nov. 14, 1944

